Field of the Invention
The present invention relates to a light emitting diode (LED) package and, more particularly, to a slim LED package that is significantly reduced in thickness without substantially reducing luminescence efficiency or while improving the luminescence efficiency.
Discussion of the Background
An LED emits light through recombination of electrons and holes by application of an electric current. An LED package means a package structure in which a light emitting diode chip, that is, an LED chip, is received. Many kinds of LED packages, particularly, a lead frame type LED package and a printed circuit board (PCB) type LED package, are well known in the art. The lead frame type LED package has a structure wherein a cavity of a housing for supporting a lead frame is filled with an encapsulation material, with the LED chip positioned in the cavity of the housing. The PCB type LED package has a structure wherein the LED chip is directly mounted on a PCB and covered with the encapsulation material.
For the lead frame type LED package, the housing supporting the lead frame has an excessive thickness, which makes it difficult to fabricate a thin lead frame type LED package. On the other hand, since the PCB type LED package does not include a housing, it can be more easily fabricated to have a thin structure than the lead frame type LED package.
However, there are many restrictions in thickness reduction of the PCB type LED package. In other words, since the thickness of the PCB type LED package is determined by thicknesses of the PCB and LED chips, and a loop height of a bonding wire even without considering the encapsulation material, it is difficult to achieve an overall thickness reduction and slimness of the PCB type LED package.
Further, the encapsulation material of the LED package, which covers the LED chip, undergoes a yellowing phenomenon by energy generated from the LED chip emitting light. Such a yellowing phenomenon is a main cause of decreased luminescence performance and lifetime of the LED package. To overcome such problems, new LED packages have been developed to have a heat sink structure. In detail, the lead frame type LED package further includes a heat dissipation slug inserted into the housing by molding. Such a structure of the lead frame type LED package requires addition of components and a complicated manufacturing process, thereby decreasing economic feasibility. For the PCB type LED package, B-T resin on which the LED chip is mounted has a low heat dissipation performance, and it is difficult to have the heat sink structure.